Several popular webmail providers are investigating a report that millions of their users' login details are being shared online by a hacker.Google Gmail, Yahoo Mail, Microsoft Hotmail and Mail.ru are among the services said to have been affected.

The security firm that flagged the issue said that it believed many of the usernames and passwords involved had not been leaked before.However, it is not clear whether users' accounts have actually been breached.Hold Security said it had obtained a total of 272 million unique pairs of email addresses and unencrypted passwords from the hacker, 42.5 million of which the company had not seen in earlier leaks.

It turned out that the details were mostly invalid. Arstechnica did a proper rundown of what occurred, hacker basically just took all the data dumps that have come out over the years (adobe, EA etc) and then removed any address that isnt @google @hotmail @yahoo or @mail.ru, combined what was left and said the logins worked on those mail services.

To his credit some did due to people using the same password on their email as these compromised websites, but it wasn't a hack of these mail services it's just compromised data that has been lingering around the internet for years.

Still everyone should always use a different password for every site and this is a good reason for that